Power unit



May 2, 1939 J. Cj AYDELOTT 2,156,957

POWER UNIT Filed April 9. 1937 Pagg-l.

inventor: John C. Agde! Ott,

Patented May 2, 1939 UNITED STATES PATENT OFFICE POWER UNIT Application April 9, 1937, Serial N0. 135,930

4 Claims.

My invention relates to power units.

An object of my invention is to provide an improved and simplified power unit including a prime mover and a generator driven thereby.

Another object of my invention is to provide an improved and simpliiied construction of the rotatable member of the dynamo-electric machine which will enable the construction of a machine of reduced axial length.

A further object of my invention is to provide an improved and simplied armature head, fan, starting gear mounting, and coupling connection which will enable the use of only one bearing for supporting the rotatable member, and the use of the rotatable member as a fly-wheel for an internal combustion engine.

A still further object of my invention is to provide an improved and simplified Ventilating arrangement for the rotatable member of the dynamo-electric machine.

Further objects and advantages of my invention will become apparent and my invention will be better understood from the following description referring to the accompanying drawing, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexeed to and forming a part of this specication.

For a better understanding of my invention, reference is made to the accompanying drawing wherein Fig. l illustrates my improved power unit including an engine and a generator driven thereby, and Fig. 2 is a partial sectional side elevational view of the generator shown in Fig. l.

Referring to the drawing, I have shown a power unit including a prime mover or internal combustion engine I0 arranged to drive a generator or dynamo-electric machine having a stationary member and a rotatable member directly supported by and coupled to the shaft of the engine I0 at one end, and supported at the other end by a bearing I2 in a hub I3, supported by arms I4 formed on the stationary member I I. In this arrangement, the generator requires no bearing for the rotatable member at the end adjacent the engine. The stationary member I I is secured to a fan housing I5, which is arranged about a ventilating fan and secured to a flange I6 formed on the engine block l0. An electric engine starting motor Il is provided which may be connected to the engine shaft through gears connected to a pinion I3 extending through an opening |9 formed in the fan housing I5.

In order to reduce the weight and size of this `power unit, it is desirable that the generator and the coupling between the engine I0 and the generator should be made as light and short as possible and yet meet the necessary magnetic and mechanical requirements of the machine. As shown in Fig. 2, the rotatable member of the generator is provided with a laminated core 20 supported on a hollow shaft 2|, which is provided with a single bearing I2 arranged to support the opposite end of the shaft from that which is coupled to the engine shaft. An armature winding 22 is arranged on the laminated core 20, and is connected to a current collecting device or commutator 23. This commutator 23 is carried by the hollow shaft 2| on the end thereof adjacent the bearing l2, and is clamped in position thereon between an annular iianged member 24, which engages a shoulder 25 on the shaft 2| and an annular ilanged member 26, which is secured in position by a nut 21 threadedly engaging a shoulder 28 formed on the hollow shaft 2|. The annular member 24 is provided with an annular axially extending iiange 29 which is radially spaced from the shaft 2| and engages one end of the laminated core 20. A plurality of axially extending openings 30 is formed in the shaft 2| through the shoulder 28 adjacent the commutator 23, and communicates with the interior of the stationary member of the generator and with the interior of the axially extending central opening 3| formed in the hollow shaft 2| A plurality of radial openings 32 also is formed through the shaft 2| and communicates with an annular passage which is formed between the flange 29 and the shaft 2 I. This provides a shaft of relatively light Weight which considerably reduces the total Weight of the rotatable member of the dynamo-electric machine.

'I'he rotatable member of the generator is provided with an armature end head which comprises an annular member 33 arranged about the end of the shaft 2| adjacent the engine and in engagement with the laminated core 20 to secure it axially of the shaft against the annular ange 29 and a flange 34 formed on the shaft 2|. An inwardly radially extending annular flange 35 engages the end 36 of the shaft 2|, and is secured thereto by screws 31 which are threaded into the end 36 of the shaft. A Ventilating fan 38 is formed on the end head and supported on a radially extending iiange 39. The fan 38 communicates with openings 40 formed in the annular member 33 of the end head which communicates with an annular groove 4| formed in the inner end of the annular member 33. This groove 4| is arranged to communicate with a plurality of axially extending Ventilating openings 42 formed in the laminated core 20 which extends between the annular groove 4i and the annular passage formed between the iiange 29 and the shaft 2l. The excitation of the stationary member I l is provided by energizing windings I Ib arranged on a plurality of salient pole pieces ila bolted to the frame II. In this manner, a Very efficient Ventilating system is provided for the machine. The Ventilating air is drawn into the stationary member of the generator through a plurality of openings 43 formed in a shield 44 arranged about the commutator end of the generator, and passes through the axially extending openings 39 into 'the central opening 3l in the shaft 2 I, radially outwardly through the openings 32, into the annular passage between the flange 29 and the shaft 2l, through the axial Ventilating passages 42 in the laminated core 20, into the annular groove 4I, through the axial passages 49 in the end head, and is blown out by the centrifugal fan 38 through openings 45 formed in the fan housing i5. The Ventilating air also is drawn through the openings 43 into the spaces between the pole pieces lia and the air gap between the armature 29 and the inner faces of the pole pieces Ila by the fan 38. This provides a Ventilating air path through the stationary member parallel to the armature cooling air path, which merges with it at the intake of the fan 38.

An axially extending annular ange 46 is formed on the outer periphery of the radially extending annular flange 39 and forms a support for an engine starting ring gear 41, which may be connected through the pinion I8 to the engine starting motor I'I. In order to support this end of the generator armature and to couple the generator to the shaft of the engine Il), I provide a flexible coupling between the unitary armature head and an extension 48 of the engine crank shaft. An annular flange 49 is formed on the end of the crank shaft 48, and a coupling plate I] is secured by bolts 5I to the flange 49. The coupling plate 59 is flexibly connected to the radially extending flange 39 of the armature head by a laminated resilient coupling disk or member formed of sheets of spring steel. This laminated coupling disk comprises two concentric annular portions 52 and 53 which are connected together by radially extending spaced apart arms 54. The inner annular portion 52 of the resilient disk is rigidly secured by screws 55 to the rotatable coupling plate 5G, and the inner periphery of the resilient laminated coupling ts on an annular axially extending ange 56 formed on the coupling plate 59. The outer annular portion 53 of the resilient coupling disk is secured to the armature head by bolts 57 which extend through openings formed in the annular flange 39, and the outer periphery of the laminated coupling nts within the annular axially extending flange 46. In this manner, the rotatable member of the generator is flexibly and resiliently connected to the engine crank shaft 48, and its inertia provides sufiicient fly-wheel effect so that it is unnecessary to provide a fly-wheel to dampen engine torque variations.

The above described flexible coupling is not my invention, but is the invention of Max. R. Hanna, and is described and claimed in his copending application, Serial No. 135,471, led April 7, 1937, and assigned to the General Electric Company, assignee of this application.

While I have illustrated and described a particular embodiment of my invention, modifications thereof will occur to those skilled in the art. I desire it to be understood, therefore, that my invention is not to be limited to the particular arrangement disclosed, and I intend in the appended claims to cover all modifications which do not depart from the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. A power unit including a prime mover having a drive shaft, a generator provided with a stationary member secured at one end to said prime mover and a rotatable member, an armature head for said rotatable member, means including a iiexible coupling for providing a driving connection between said prime mover drive shaft and said armature head and for supporting one end of said rotatable member, and means including a bearing for supporting the other end of said rotatable member on said generator stationary member.

2. A power unit including a prime mover having a drive shaft, a generator provided with a statio-nary member secured at one end to said prime mover and a rotatabley member, an armature head for said rotatable member, means including a flexible coupling for providing a driving connection between said prime mover drive shaft and said armature head and for supporting one end of said rotatable member, a starting motor carried by said prime mover having a pinion gear, a ring gear carried by said armature head for engaging said starter motor pinion gear to start said prime mover, means including a fan associated with said armature head for ventilating said generator, and means including a bearing carried by said stationary member of said generator for supporting the other end of said rotatable member.

3. A power unit including a prime mover having a drive shaft, a generator provided with a stationary member secured at one end to said prime mover and a rotatable member, said rotatable member having a laminated core, an annular member arranged to secure together said laminated core on said rotatable member, a fan associated with said annular member, ventilating openings formed in said laminated core, openings formed in said annular member providing communications between said laminated core Ventilating openings and said fan, means including a flexible coupling for providing a driving connection between said prime mover drive shaft and said rotatable member and for supporting one end of said rotatable member, and a bearing arranged to support the other end of said rotatable member on said generator stationary member.

4. A power unit including a prime mover having a drive shaft, a generator provided with a stationary member and a rotatable member, a unitary structure including an annular member arranged to provide an armature head for said rotatable member, a fan formed on said unitary structure, means including a flexible coupling for providing a driving connection between` said prime mover drive shaft and said unitary structure armature head and for supportingone end of said rotatable member, and means including a bearing for supporting the other end of said rotatable member on said generator stationary member.

JOHN C. AYDELOTT. 

